The Carbon Footprint of MRI Access: A Population-Based Study Evaluating Excess Patient Travel and CO2 Emissions in Nova Scotia.

INTRODUCTION

The carbon footprint of imaging equipment in radiology is high, but the impact of patient travel for imaging is unclear. This study aimed to quantify distances traveled by ambulatory patients for outpatient MRI, determine the proportion traveling beyond their nearest MRI facility, and estimate the associated excess carbon dioxide equivalent (CO2e) emissions.

METHODS

With research ethics board approval, we retrospectively analyzed provincial MRI data from 2023. Distances from patient home address to the nearest and attended MRI facilities were calculated. CO2e estimates were derived using an online tool (www.carbonfootprint.com/calculator.aspx) with average vehicle size and emissions.

RESULTS

In 2023, 40 062 provincial MRI scans were performed; isolating single visits for adult patients yielded 27 755 data points. Of these, 19.5% (n = 5400) traveled beyond their nearest MRI facility. Mean round-trip travel was 60.4 km for those attending their nearest site versus 295.6 km for those traveling further (P < .0001). The excess travel produced ~288 metric tons of additional CO2e, equivalent to emissions from 61 large-size gasoline-powered cars driven for 1 year or carbon sequestered by 4762 tree seedlings grown for 10 years.

CONCLUSION

Nearly one-fifth of patients traveled farther than necessary for MRI, generating substantial avoidable emissions. Aligning MRI service distribution with population density could lessen the environmental impact of medical imaging.